Corticosteroids are widely prescribed therapeutics. Systemic, topical and injected formulations are routinely employed for a variety of ophthalmic conditions. In particular, topical applications account for the widest use of non-invasively delivered corticosteroids for ocular disorders. This approach, however, suffers from low bioavailability and, thus, limited efficacy.
Dexamethasone, member of the glucocorticoid class of steroid hormones, acts as an anti-inflammatory and immunosuppressant. Ocular formulations are used that allow for diffusion of dexamethasone across an ocular, membrane, however, such topical formulations suffer from slow, inadequate and uneven uptake. Because current ocular delivery methods achieve low ocular exposures, frequent applications are required and compliance issues are significant.
Topical dexamethasone applications involving ocular iontophoresis have not been described. Based on commercially-available, columbic-controlled iontophoresis for topical applications to the skin of a variety of therapeutics, it is clear that even well understood pharmaceuticals require customized formulations for iontophoresis. These alterations maximize dosing effectiveness, improve the safety and manage commercial challenges. The known technical formulation challenges presented by dermatological applications may translate in to ocular delivery. However, ocular iontophoresis presents additional formulation needs. Thus, developing novel formulations that are ideally suited for ocular iontophoretic delivery of corticosteroids is required. Such formulations include many variables, including: API concentration, solute, excipients, stabilizers, buffering agents, delivery applicator, iontophoretic dose, etc. Developing corticosteroids suitable for non-invasive local ocular delivery will significantly expand treatment options for ophthalmologists.